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Lichens Pan-Z (2007) - Flora of New Zealand Lichens - Revised Second Edition Pan-Z
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Strigula Fr.

STRIGULA Fr., 1823

=RACIBORSKIELLA Höhnel, 1909

Type : Strigula smaragdula Fr.:Fr.

Type : Raciborskiella talaumae (Racib.) Höhnel [=Clypeolum talaumae Racib. (=Strigulajanierensis (Müll.Arg.) Lücking]

Description : Flora (1985: 563).

Key

1
Thalli saxicolous
2
Thalli corticolous or foliicolous
6
2
Ascospores transversely septate
3
Ascospores muriform
5
3
Ascospores mostly 3–7-septate
4
Ascospores 1-septate, cells separating at maturity, 22–32 × 4.6–5 μm
4
Thallus silicolous; ascospores 7-septate, 22–33 × 5.5–7.5 μm
Thallus calcicolous; ascospores (1–)3(–5)-septate, 15.5–26.5 × 4.5–8.5 μm
5
Perithecia 0.32–0.58 mm diam.; ascospores submuriform, 23–36 × 7–11.5 μm
Perithecia 0.42–0.82 mm diam.; ascospores muriform, 37–63 × 10–19 μm
6
Thallus corticolous
7
Thallus foliicolous
10
7
Ascospores transversely septate
8
Ascospores submuriform; 25–27 × 8–9 μm; macroconidia 3-septate fragmenting into 4 part-spores
8
Ascospores more than 1-septate
9
Ascospores 1-septate, 13–20.5 × 3.5–5 μm
9
Thallus olivaceous to yellow-brown; ascospores 13–20.5 × 3.5–5 μm
Thallus dark grey-green; ascospores 6–10 × 2–3.5 μm
10
Thallus whitish, forming pale mosaics; ascospores 3–6-septate, (12–)16–32 × 4.5–7.5 μm
Thallus grey-white or pale greenish white; ascospores 5-septate, 17–22 × 3.5–5 μm
11
Thallus developing on upper surface of leaves (epiphyllous); paraphyses simple
12
Thallus developing on lower surface of leaves (hypophyllous); paraphyses branched and anastomosing
12
Ascospores 1-septate
13
Ascospores 3-septate
23
13
Involucrellum constantly present
14
Involucrellum absent; ascospores (12–)15–22 × 4–6 μm
14
Ascospores breaking into 2 part-cells in ascus
15
Ascospores not breaking into 2 part-cells in ascus
17
15
Ascospores 8–12 μm long
16
Ascospores 13–16 × 3.5–5 μm
16
Asci clavate, 28–35 × 5.5–7 μm; ascospores 8–10 × 2–2.5 μm
Asci cylindrical, 40–60 × 4–5 μm; ascospores 9–12 × 2 μm
17
Ascospores more than 12 μm long
18
Ascospores 8–12 × 2–3 μm
18
Thallus green to grey-green
19
Thallus pale bluish green to whitish; ascospores 17–25 × 4–7 μm
19
Involucrellum not uniting several perithecia; ascospores without terminal appendages
20
Involucrellum uniting several perithecia; ascospores with terminal appendages, (12–)13–15 × 4.5–5.5 μm
20
Thalli circular or effigurate, not forming a reticulum
21
Thalli with dichotomously branched lobes forming a reticulum; ascospores 15–16(–18) × 4.5–5.5 μm
21
Pycnidia not producing polarilocular macroconidia
22
Pycnidia producing polarilocular macroconidia, 13–17 × 3–4.5 μm; ascospores 16–18 (–22) × (3–)4.5–5 μm
22
Thallus dark grey-green, bordered by a thin, black prothalline line; ascospores 1(–3)-septate, 14–22 × 3–5 μm; macroconidia simple, 10–12 × 2–3 μm
Thallus bright-green to grey-green, without a marginal, black, prothalline line; ascospores 1-septate, 14–24 × 4.5–5 μm; macroconidia 1-septate, (12–)14–18(–21) × 3–4 μm
23
Thallus dark grey-green; ascospores (1–)3-septate, 10–16 × 2–3 μm ; macroconidia bacillar, 4–7 × 2 μm
Thallus pale green-grey to green-white; ascospores (1–)3-septate, (12–)15–24 × 3.5–6 μm; macroconidia filiform, (25–)30–65 × 2–2.5 μm

Strigula is a widespread genus of some 55 species (Kirk et al. 2001; Roux & Sérusiaux 2004), included in the family Strigulaceae (Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005). Many taxa are foliicolous and of mainly tropical distribution, growing on leaves between the cuticle and epidermis (i.e. subcuticular) of the host (see Santesson 1952; Lücking 1992; Farkas & Sipman 1997; Malcolm & Malcolm 2001; Roux & Sérusiaux 2004). Recently it has become clear that taxa of Strigula also colonise bark and rock, being found moreover at higher latitudes (Roux & Bricaud 1993; McCarthy 1997), and one species is lichenicolous (Etayo 2002). As a result, many new taxa were described or transferred to Strigula from other genera, especially from Porina. Harris (1995: 152–153) places Raciborskiella in synonymy with Strigula, noting that the occurrence of species of Raciborskiella on the underside of leaves is a character of the photobiont and that asci, ascospores, microconidia and macroconidia are identical in the two genera, although Lücking (1992: 49) and Farkas & Sipman (1997: 192) keep it as an independent genus. Nomenclatural problems in Strigula are discussed in Hawksworth (1986b). A key to saxicolous taxa is given in McCarthy (1997). For additional information see also Roux & Bricaud (1993), Harris (1995), McCarthy (1995e, 1997, 2001a), McCarthy & Malcolm (1996b), McCarthy et al. (1996a), Etayo (2002), and Roux & Sérusiaux (2004). Strigula is highly speciose in New Zealand with nearly half of the known species in the genus occurring here. This account discusses 24 species although a regional monograph on the genus is still much needed.

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